Recently, there has been a growing interest in hemotropic mycoplasmal species (also known as the hemoplasmas), the causative agents of infectious anemia in several mammalian species. In felids, two different hemoplasma species have been recognized: Mycoplasma haemofelis (formerly Haemobartonella felis) and ‘Candidatus Mycoplasma haemominutum.’
Haemobartonella felis, the causative agent of feline infectious anemia, was recently reclassified within a newly defined group of hemotropic mycoplasmal species (also known as the hemoplasmas). Sequencing of the 16S ribosomal RNA (rRNA) gene of different feline isolates has resulted in the recognition of two different species (Berent et al. 1998. Am J Vet Res 59:1215-20; Foley et al. 1998. Am J Vet Res 59:1581-8; Messick et al. 1998. J Clin Microbiol 36:462-6; Rikihisa et al. 1997. J Clin Microbiol 35:823-9; Tasker et al., 2003. J Clin Microbiol 41:3877-80), Mycoplasma haemofelis and ‘Candidatus Mycoplasma haemominutum’ (Johansson et al. 1999. FEMS Microbiol Lett 174:321-6; Neimark et al. 2001. Int J Syst Evol Microbiol 51:891-9; Rikihisa et al. 1997 J. Clin. Microbiol. 35:823-829), that parasitize feline red blood cells (RBC) (Messick et al. 1998. J Clin Microbiol 36:462-6). Experimental infection studies have shown that the two species differ in pathogenicity (Foley et al. 1998. Am J. Vet Res 59:1581-1588; Tasker et al. 2003. J Clin Microbiol 41:3877-80; Westfall et al. 2001. Am J Vet Res 62:687-91): cats experimentally infected with ‘Candidatus M. haemominutum’ exhibit minimal clinical signs and anemia is not usually induced whilst M. haemofelis infection often results in severe hemolytic anemia. Since M. haemofelis and ‘Candidatus M. haemominutum’ cannot be cultured in vitro, diagnosis until recently has relied upon cytological identification on blood smears (Bobade et al. 1987. Vet Parasitol 26:169-72). However, the development of new molecular methods has facilitated the sensitive and specific identification and quantification of these agents (Berent et al. 1998. Am J Vet Res 59:1215-1220; Jensen et al. 2001. Am J Vet Res 62:604-8; Tasker et al. 2003. J Clin Microbiol 41:3877-80), and PCR analysis is now the diagnostic method of choice for identification of hemoplasma infections. There is still little knowledge of the epidemiology of these agents. Both species have been shown to exhibit worldwide geographical distribution (Clark et al. 2002. Aust Vet J 80:703-4; Criado-Fomelio et al. 2003. Vet Microbiol 93:307-17; Jensen et al. 2001. Am J Vet Res 62:604-8; Tasker et al. 2001. Vet Microbiol 81:73-8; Tasker et al. 2003. J Clin Microbiol 41:3877-80; Watanabe et al. 2003. J Vet Med Sci 65:1111-4) and isolates from three different continents have shown near sequence identities (Tasker et al. 2003. J Clin Microbiol 41:3877-80). We now unexpectedly identified a third hemoplasma agent, “Candidatus Mycoplasma turicensis,” which has been deposited with ATCC under the Budapest Treaty as PTA-6782.